This type of gas sensor is in practical use as, for example, an A/F sensor disposed on an exhaust passage of an engine. To make an actual air-fuel ratio detected by the A/F sensor agree with a target air-fuel ratio, feedback control is performed. When the engine is operated, there is a concern that noise generated due to the engine operation may be superimposed on a detection signal of the A/F sensor, resulting in decrease of the accuracy in detecting the air-fuel ratio. Thus, a technique, in which a low-pass filter circuit is provided in a control circuit part, which receives a detection signal of an A/F sensor, to remove noise by using the low-pass filter circuit, is in practical use.
In addition, for example, patent literature 1 focuses on the fact that if an exhaust pulsation occurs when a supercharger operates, the exhaust pulsation is superimposed on a sensor detection signal as noise. Patent literature 1 discloses a technique in which, in a supercharging state, a detection signal of a gas sensor is subjected to a filtering process of a filtering means, and the filter mode is corrected based on the pressure in an intake pipe.